Fundamentals I Test 4 Pittler – Flashcards
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| Plants which consistently have offspring with same trait as parent are ___. |
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| True breeding or Homozygous |
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| What is the name for crossing true breeding plants with two distinct forms of a trait? What is the result of this? |
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| Monohypbrid Cross (Heterozygous): progeny only show one form of the trait |
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| Describe a test cross. |
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| Plant with recessive trait is crossed with plant of unknown genotype. |
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| Describe the progeny of a monohybrid cross. |
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1/4 Dominant - True breeding; 1/2 Dominant - Not true breeding; 1/4 recessive 3:1 dominant to recessive |
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| What are the two parts of the law of probability? |
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1. probability that multiple independent events will occur together is the product of their chances of happening separately 2. chance an event can occur in multiple independent ways is the sum of the individual chances |
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| What state that each organism possesses two distinct separable units (alleles) for each trait inhetited from each parent? |
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| Law of segregation |
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| What state that each organism possesses two distinct separable units (alleles) for each trait inhetited from each parent? |
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| Law of segregation |
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| What is another name for Mendel's units or elementum?; It is also defined as versions of the same gene that differ in DNA sequence at one or more sites. |
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| Alleles |
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| What indicates the combination of alleles present in an organism? |
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| Genotype: Homozygous (same alleles) ; Heterozygous (different alleles) |
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| What indicates the trait observed? |
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| Phenotype |
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| What is the most common phenotype called? |
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| Wildtype; wildtype allele=most frequent allele |
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| What indicates the patterns with which the mutant phenotype is associated? What are the three most common types? |
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| Mode of Inheritance; Autosomal Recessive, Autosomal Dominant, ; X-linked Recessive |
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| What mode of inheritance is described by these characteristics? Heterozygotes exhibit affected phenotype, males ; females equally affected and may transmit the trait, and affected phenotype does not skip generations. |
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| Autosomal Dominant Inheritance |
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| What mode of inheritance is characterised by these statements?; Heterozygotes carry allele but don't exhibit it, males & females equally affected and may transmit the trait, and may skip generations. |
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| Autosomal Recessive Inheritance |
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| What states that two genes on different chromosomes segregate their alleles independently? |
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| Law of Independent Assortment (inheritance of one allele doesn't influence inheritance of another) |
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| What is a symbolic representation of family relationships and inheritance of a trait? |
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| Pedigrees |
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| What is a structure that consists primarily of DNA ; proteins that are duplicated ; transmitted during mitosis or meiosis? |
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| Chromosomes |
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| Distinguish between Heterochromaticn ; Euchromatin. |
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Heterochromatin stains dark, noncoding Euchromatin stains light, protein coding |
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| What are the three locations you find centrosomes on the chromosome? |
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| Metacentric=middle, Acrocentric=close to end, Submetacentric=off center, Telocentric=end |
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| What are the two arms of a chromosome? |
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| P arm = short arm ; Q arm = long arm |
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| What is the basic unit of chromatin?; What does it consist of? |
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| nucleosome; 146bp DNA ; 8 histones |
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| Which histone helps compact nucleosome into 30nm fiber? |
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| H1 |
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| What is a critical determinant of chromatin structure? |
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| Histone tails; methylation ; acetylation leads to genomic imprinting ; regulation |
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| What does a normal karyotype consist of? |
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| 23 diploid chromosomes; 46 total chromosomes |
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| What is the term for a cell missing a single chromosome or having an extra one? |
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| Anueploid |
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| What is the term for cells that contain a normal chromosome constitution? |
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| Euploid |
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| How are chromosomes ordered on a Karyotype? |
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| by size ; centromere position |
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| What states that modifications of the histone tails act as marks that can be read by other proteins to control the expression or replication of chromosomal regions? |
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| Histone Code Hypothesis |
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| What is described as heritable changes not caused by mutation in the DNA? |
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| Epigenetics |
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| What is genomic imprinting? |
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| Each parent passes on a gene for a trait, but only one is expressed.; The other is "imprinted" ie. Barr Bodies |
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| What disease is caused by a defect in imprinting ; causes kidney tumors in children? |
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| Wilms Tumor |
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| What leads to gene silencing? |
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| Methylation of C residues in CpG island |
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| What disease is caused by a DNA methylation problem? |
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| Rett Syndrome |
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| What is at the tips of chromosomes and what sequence do you find here? |
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| Telomeres; TTAGGG |
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| What chromosomal part is found between the protein-rich areas and the telomeres? |
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| Subtelomeres |
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| T/F Subtelomeres do include some protein-coding genes? |
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| True |
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| What is the location where spindle fibers attach to the centromere? |
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| Kinetochore |
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| What technique uses DNA probes that are complimentary to specific base sequences? |
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| FISH (Flourescence in situ Hydrogenation) |
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| What subdiscipline within genetics focuses on chromosome variations? |
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| Cytogenetics |
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| What disease is a trisomy of chromosome 21?; What about XO and XXY? |
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| Trisomy 21=Down's, XO=Turner (female), XXY=Klinefelter (male) |
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| What are the three most common trisomy chromosomes? What do they have in common? |
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| 13 (Patau), 18 (Edward), & 21(Down); have lowest gene densities |
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| What is the term for an extra chromosome set? What causes this? |
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| Polyploidy; 2 sperm fertilizing one egg or haploid sperm fertilizing diploid egg |
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| What is the term for having a segment of the chromosome reversed? |
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| Inversion |
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| What is the term for two chromosome arms exchanged in part or entirely? |
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| Translocation |
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| What is a chromosome with identical arms? |
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| Iso chromosomes |
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| What causes a ring chromosomes? |
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| Deletion of telomeres |
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| What is a common cause of aneuploidy resulting in a gamete with one extra chromosome & another with one missing chromosome? How do the results differ between the 1st and 2nd meiotic anaphase division? |
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| Nondisjunction; 1st - copy of each homolog in gamete & two cells with no copies; 2nd - both sister chromatids in one gamete, one with no copy, and two normal cells (better of the two scenarios) |
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| What does nondisjunction cause? |
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| euploidy |
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| What is the term for different nonhomologous chromosomes that exchange portions of chromosomes or combined parts? |
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| Translocation |
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| What describes chromosomes that have a region flipped in orientation compared to wild type chromosomes? What are the two types? |
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Inversion Paracentric: inverted region doesn't include centromere Pericentric: inverted region includes centromere |
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| In what two ways can mutation occur at the molecular level? |
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| 1. Substitutin one DNA base for another; 2. Adding or deleting bases |
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| The mutation of what protein prevents people from being infected with HIV? |
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| CCR5 |
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| Does mutation refer to genotype or phenotype?; What about mutant? |
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| Mutation=Genotype;;;; Mutant=Phenotype |
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| What is a mutation that does not alter the phenotype? |
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| Polymorphism |
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| T/F A mutatuion produces individuals with variant phenotypes who are better able to survive in a specific environment. |
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| True |
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| What type of mutation is limited to an individual and not transmitted to offspring? |
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| Somatic Mutations |
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| What type of mutation have the possibility of transmission to offspring? |
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| Germline Mutations |
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| Describe the mutation in red blood cells that leads to Sickle Cell Anemia. |
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| T in DNA anti-sense strand is changed to A = Glu is changed to Val |
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| What is the result of a beta hemoglobin mutation that results in too few protein molecules? |
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| Thalessemia (homozygous mutation has more severe phenotype than heterozygous) |
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| What comprises 60% of bone ; cartilage?; What is it's structure? |
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| Collagen; two α1 helices and one α2 helix |
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| Mutation in what protein is responsible for Alzheimer disease? Where is this protein found & what is it's function? |
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| Presenilin 1; anchored in Golgi membrane, monitors beta amyloid usage (accumulation placques form) |
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| What are the four main characteristics of Spontaneous mutation? |
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| 1. De novo or new; 2. Not caused by exposure to known mutagen; 3. Errors in DNA replication; 4. DNA bases have slight chemical instability |
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| Spontaneous mutations can produce slightly changed ____s which cause problems for the enzymes that are trying to recognize the sequence. |
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| tautomers |
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| What is the mutation associated with Familial hyperchlesterolemia? |
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| Deficient LDL receptors |
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| What mutation is associated with Hemophilia A? |
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| absent or deficient Factor VIII protein |
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| What three things is spontaneous mutation rate dependent on? |
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| 1. Size dependence; 2. Sequence dependence; 3. Hot spots |
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| T/F; Most mutations are in coding regions of genes. |
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| False; most are in noncoding regions |
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| What are the three mutational hot spots, and what is their source? |
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1. Short Repetitive Sequence: pairing of repeats may interfere w/replication or repair enzymes 2. Palindromes: associated w/insertions or deletions 3. Duplications of Larger Regions: mispairing during meiosis |
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| What are two major causes of insertions or deletions? |
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| Hairpins ; Non-Reciprocal Recombination |
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| What chromosome is effected by alpha thalassemia?; What are the effects of different numbers of this chromosome? |
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| 16; 4=normal, 3=considered normal, 2=mild anemia, 1=severely anemic |
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| What is the term for a chemical that causes mutation? |
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| Mutagen |
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| What is the term for chemicals that cause cancer? |
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| Carcinogens |
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| Which mutation inducer causes removal of a DNA base that is replaced with a mismatch pair? |
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| Alkylating agent |
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| Which mutation inducer addes or deletes a single base? |
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| Acridine dyes |
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| Which mutation inducer alters base pairs so that A-T replaces G-C or vice versa? |
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| Mutagenic chemicals |
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| Which mutation inducer deletes a few bases or breaks chromosomes? |
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| X-rays ; other radiation |
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| T/F; Ames is an in vivo test of mutagenicity of a substance using Salmonella bacteria with a mutation in a gene. |
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| False; in vitro |
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| What amino acid is involved in the mutation used in the Ames test? |
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| Histidine |
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| Describe the least penetrating radiation exposure. |
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| Alpha; least energetic, shortest-lived, absorbed by skin; Uanium ; radium |
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| Describe the second most penetrating radiation. |
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| Beta; tends not to harm unless eaten or inhaled; tritium, C-14, ; strontium-70 |
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| Describe the most penetrating type of radiation. |
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| Gamma; goes all the way through body, kills cancer cells; plutonium ; cesium |
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| Mutations in what types of cells can cause cancer? |
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| Oncogenes or Tumor Suppressor Genes |
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| What type of mutation is caused by a change of a single nucleotide to one of the other three possible nucleotides? |
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| Point Mutation |
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| Differentiate between a Transition and a Transversion. |
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Transition: Purine replaces Purine or Pyrimidine replaces Pyrimidine Transversion: Purine replaces Pyrimidine or vice versa |
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| What is a point mutation that exchanges one codon for another causing substitution of an amino acid? |
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| Missense Mutation (ie. Sickle Cell) |
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| What type of mutation has a change in amino acid from a normal codon to a premature stop codon? |
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| Nonsense mutation (ie. Becker muscular dystrophy or Ehlers-Danlos) |
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| What type of mutation alters a site where introns would normally be removed from mRNA? |
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| Splice Site Mutations |
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| What is the term for a particular form of insertion in which identical sequences are found side by side? |
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| Tandem Duplication |
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| What is the term for a DNA sequence reminiscent of a gene but isn't translated? Can it be transcribed? |
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| Pseudogenes; may or may not be transcribed |
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| What phenomena is described as expansion of the triplet repeat and coincident increase in severity of phenotype occuring with subsequent generations? |
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| Anticipation (ie. Myotonic dystrophy) |
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| T/F Different mutations may cause the same disorder. |
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| True |
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| T/F All mutations impact protein function. |
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| False; Silent Mutations don't alter AA sequence because they form Synonymous Codons |
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| What type of mutation only produces a phenotype under particular conditions? |
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| Conditional Mutations |
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| What number of bases can be replaced by Nucleotide ; Base Excision Repair? |
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| Nucleotide: ;30; ;; Base: 1-5 ; (ie. Xeroderma Pigmentosa) |
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| What occurs when enzymes detect nucleotides that do not base pair in newly replicated DNA?; How is it detected? |
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| Mismatch Repair; Proofreading |
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| What protein monitors repair of damaged DNA? |
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| p53 |
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| What is a group of diseases caused by loss of cell cycle control? |
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| Cancer |
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| What type of tumer grows in place? What type invades nearby tissues? |
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| Benign=stationary, Malignant=invasive |
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| T/F; More often cancer-causing mutations occur in somatic cells ; is a genetic disease at the whole-body level. |
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| False; they are usually somatic cells, but it works at the cellular level not the whole-body |
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| Loss of control over what portion of the chromosome can contribute to cancer? |
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| Telomere |
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| T/F; Germline inherited cancers must have a second mutation in the somatic cell to spark cancer in the body. |
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| True |
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| What are two unique characteristics of cancer cells? |
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| Rounder (doesn't adhere to normal cells) & plasma membrane is more fluid |
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| What is secreted by tumor cells that are starved for Oxygen? |
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| Vascular Endothelial Growth Factor - stimulates capillaries to extend branches toward tumor |
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| Are Proto-oncogenes normal cells or mutated cells? |
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| Normal |
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| Can oncogenes effect viral & transcribing genes nearby? |
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| Yes |
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| T/F Reciprocal translocation produces two different fusion genes. |
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| True |
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| Is phosphorylation normally present in cancer cells? |
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| No |
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| What type of gene normally stops cells from dividing? |
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| Tumor Suppressor Genes |
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| What states that two mutations, one in each copy of the RB gene, are required to cause a phenotypic result? |
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| Knudson's Two Hit Hypothesis |
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| What is the breast cancer susceptibility gene, and how does it function? |
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| BRCA1; one mutation is inherited ; a second must be acquired at the cellular level |
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| What is described as a change in one gene can compensate for the mutation in another, could be the result of epigenetics? |
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| Incomplete Penetrance |
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| What are the three environmental impacts of cancer? |
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| Exposure to carcinogens, Exposure to radiation, and Variation in diet |
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| What type of vegetables can lower cancer risk? |
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| Cruciferous |
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| What are the 5 treatments for breast cancer? |
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| Remove tissue, Destroy tissue, Use phenotype to select drug, Use genotype to select drug, Genomic level |
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| What four properties of DNA are most genetic technologies based on? |
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1. DNA can be cut at specific sites 2. Different lengths of DNA can be size-separated by electrophoresis 3. Single strand of DNA will stick to its complement 4. DNA can be copied by a polymerase enzyme |
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| T/F; Most recognition sites where restriction enzymes cut are palindromes. |
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| True |
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| What charge does DNA have?; Describe it's movement on a gel. |
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| Negative; moves toward positive electrode, shorter lengths move faster |
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| What are the two methods for analyzing the way in which DNA sticks to its complement? |
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| PCR and Southen Blotting (slow & requires large amount of DNA) |
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| What is a method for producing large quantities of a specific region of DNA from tiny quantities? |
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| Polymerase Chain Reaction (PCR); requires much less DNA than Southern Blotting |
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| What DNA polymerase can copy DNA? |
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| Taq DNA Polymerase |
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| What are the possible samples for PCR? Do they have to be pure? |
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| hospital tissue, single hair, dried blood, mummified tissue, frozen tissue; No-can be pure or impure |
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| What method uses mRNA as a marke of gene expression? What is it used for? |
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| Microarrays; measure differences in gene expression between two cell types or to study chromosomal aberrations in cancer cells (diagnose & stage tumors) |
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| What are the problems with microarray analysis? |
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| Gene expression≠mRNA concentration, Difficult to interpret, Standardization b/w labs, Lots of noise, Lots of genes, Low sample size |
